The present work aims to establish the possibility of using local clays to treat wastewater. Thus, three clay samples extracted from two localities in the south of Côte d'Ivoire have been studied in their crude state. The qualitative physicochemical study that consisted in measurement of pH variation and argillaceous particles zeta potential showed that the Nieki-Agneby clay and the Beige Anyama clay presented disposal to uptake phosphate ions in solution at pH 5. For each clay, it is shown that the tension accompanying the sorption of a phosphate ion could be estimated to -5 mV. Differences in their composition and in the number of hydrating molecules of water were also accessible. The quantitative study performed with the Nieki-Agneby clay thereafter consisted following the sorption kinetic. The adsorption was found to reach the maximum after 5 h. of exchange, and almost 400m g phosphate ions in per gram of clay were fixed. Future studies will focus on the modification of these materials in order to increase their sorption capacity.

Expansive behavior is usually observed in soils, which contain fractions of clay minerals in their composition. Water absorption of clay particles and change of natural water content of soil up to plastic limit and down to shrinkage limit will cause significant volume change in expansive soil and will result in severe damages to the structures, buildings and foundations. Swelling potential is directly related to clay minerals activity and soil plasticity. Besides all the parameters expressing composition of soil, environmental conditions provide conditions to release the swelling potential.In the present study, in order to observe effects of soil mineralogy, plasticity, and compaction indices such as water content and dry unit weight, swelling behavior of five clay soils has been investigated. Results of experiments indicate that parameters like clay minerals, absorbed cations to clay sheets, plasticity index, clay size fraction, initial water content and dry density have significant influence on the swelling behavior of compacted clays.

The article discusses the effect of calcined clays on the properties of Portland cement. An optimal method for calcining clays is proposed, which makes it possible to reduce the proportion of Portland cement clinker in cement to 60% and increase the strength characteristics from 55 MPa to 79 MPa. The study of the composition and structure of clays made it possible to select the optimal heat treatment parameters, at which the calcination products are characterized by the highest pozzolanic activity. It is shown that the use of alkali-activated calcined clays significantly increases the strength and durability of hardened cement binders compared to the composition without additives. In addition, calcined clays increase the frost resistance of cement in a 5% NaCl solution. The obtained experimental data are confirmed by thermodynamic calculations and the results of scanning electron microscopy.

Adsorbent clays have an excellent capacity of binding mycotoxins. This work assesses the potential of natural zeolite and bentonite for Aflatoxin M1 (AFM1) removal from milk and water. Artificially contaminated milk and water samples (with 50 and 500 ng/L AFM1) were contacted with 5 gr/L of sorbents, including zeolite powder, zeolite beads and bentonite powder. Amounts of residual AFM1, and also protein, fat and lactose content were determined in treated milks. Results showed that the adsorption of AFM1 on natural zeolite and bentonite varied from 63 to 100% based on the type of clays and AFM1 concentration. For zeolite powder, the adsorption treatment reduced the content of total protein. Adsorbent clays reduce the AFM1 content of milk by surface removal of them. These adsorbents do not destroy or inactivate the toxin and do not produce toxic residual. The extent of toxin removal depends on clay contact surface and by using proper clays; it is possible to reduce the AFM1 content of milk below the allowed level.

Interactions between Cd, pillared clays and chalcogenedies have been studied using nanomineralogical experiments. XRD, DSC and chemical analysis. The synchrotron-based X-ray absorption spectroscopy (XAS) was applied to characterize the reaction phases. The mean bond lengths between, Cd-S, Fe-S, Sb- S, Cd-Cd (in chalcogenedies), Al-Cd, Cd-Ti, and Fe-Cd, (in pillared clays) were determined by XAS method. The ligands information around cadmium atoms was obtained directly from EXAFS and indirect from XANES experiments. Cadmium bearing phases and diffusion of Cd in phases were distinguished by HRXRD, SEM and EPMA. The XAS analysis showed that cadmium sorbed onto pillared clays through a distinct mechanism. These data indicated that the major adsorbent of Cd is a complex of Al, Ti and Fe pillared clays.